Fastening devices are known that allow two strap portions to be easily and securely fastened and unfastened by a user. A buckle, for example, is used to fasten two ends of a belt or other strap. Most commonly, one end of the belt or strap is permanently attached to the buckle, and the other end may be fastened to the buckle in an adjustable manner. Other fastening devices allow for adjustments to both ends of the belt or strap, although making adjustments to one of the ends typically also requires removing the other end. Many fastening devices utilize moving parts, such as an articulating prong that is inserted through a hole in a strap to hold the strap in place. There is a continuing need for further improvements in the design of fastening devices, such as buckles.